Locking tau-square or like article



K. w. HARRISON 3,086,291

LOCKING T-SQUARE OR LIKE ARTICLE April 23, 1963 Filed April 25, 1962 FlG.l

z INVENTOR KENNETH W. HARRISON ATTOR N EY United States Patent .0

3,086,291 LOCKING T-SQUARE R LIKE ARTICLE Kenneth W. Harrison, 7171 Mortenview Drive, Taylor, Mich. Filed Apr. 25, 1962, Ser. No. 190,032 3 Claims. (Cl. 33-80) This invention relates to T-squares or tools, instruments or the like which are or may be used in a manner similar to T-squares, that is, inthe arts of scribing on metals, cloth marking or cutting, carpentry, masonry or other arts where such a device could be used. In order to disclose the construction, operation and advantages of the invention, however, a draftsmans T-square in conjunction with a drawing board have been illustrated in the accompanying drawing and the description has been directed thereto, although the invention is subject to wider applications as just mentioned.

An object of the invention is the provision of means for locking a T-square or like article to a drawing board or operating table or the like, so that in drawing or otherwise working on the paper or work piece both hands are free to do the work with complete assurance that the T-square will not slip out of the true position in which it has been set.

Another object of the invention is the provision of a T-square or like article with adjustable releasable locking means for securing the article to a board or table, which means is simple in construction, inexpensive in cost of manufacture, and of a nature to save time for the user.

A further object of the invention is the provision of a locking T-square or like article which may not only be readily adjustable to fit boards or tables of different widths but which may also be readily removed from or repositioned on a board or table in locked position without the need to operate the locking means.

The above as well as additional objects will be clarified in the following description wherein reference numerals refer to like-numbered parts in the accompanying drawing. It is to be noted that the drawing is intended primarily for the purpose of illustration and that it is therefore neither desired nor intended to limit the invention necessarily to any or all of the details shown or described except insofar as they may be deemed essential to the invention.

Referring briefly to the drawing,

FIG. 1 is a top plan view of a T-square applied to a drawing board, illustrating an embodiment of the invention.

FIG. 2 is an enlarged side view taken along the line 2-2 of FIG. 1.

FIG. 3 is an enlarged sectional view taken on the line 3-3 of FIG. 1.

FIG. 4 is a view taken along the line 44 of FIG. 1, illustrating a feature of the invention.

FIG. 5 is a fragmentary enlarged elevational view of I a detail.

Referring in detail to the drawing, the numeral designates a drawing board whose opposed longitudinal edges 11 and 12 are mutually parallel.

A T-square is shown at 13, composed of the usual elongated stem or arm 14 and, firmly secured to one end of the arm, the usual guide 15 which projects below the bottom surface of the arm 14 to provide a shoulder which is engageabie with the edge of the board in the usual manner.

In carrying out the present invention a median longitudinal groove is provided in the top surface of the arm 14, as indicated at 16. A second guide 17 which in general conformation and dimensions may be substantially similar to the guide 15, is provided with a transverse 3,086,291 Patented Apr. 23, 1963 "ice passage through which the arm 14 extends to slidably mount the guide 17 on the arm. For practical assembly purposes, a recess 19 may be provided in the top surface of the guide 17 into which a plate 20 is set flush with the adjacent top surfaces of the guide, and the plate may be secured to the guide by means of screws 2101. Thus the plate provides a roof over the passage 18.

Formed in the plate 20 is an internally threaded socket or passage-enclosing boss or the like 21 which is positioned above the passage 18. A screw 22, preferably in the form of a thumb screw or wing screw, extends through the boss 21 in threadable engagement therewith, into the groove .16 in the arm 14.

On the end of the screw which projects into the groove 16 an enlarged substantially disc-shaped lug of compressible or somewhat resilient material such as, for example, a suitable rubber, is rotatably or loosely secured. Such a lug is shown at 23. By providing a reduced neck 24 on the end of the screw and a widened head 25 on the extremity of this neck, and by providing a recess in the lug complementary to the neck and head, it is obvious that the lug, owing to its elasticity, may be readily slipped over the neck and head to secure it to the screw.

In use, the guide 17 may be positioned to snugly engage the edge of the board 10 opposite the edge engaged by the fixed guide 15, that is, the edge 12 of the board, in an obvious manner. After the guide 17 has been so positioned on the arm 14, the screw 22 is tightened to force the lug 23 downward into the groove 16 against the base thereof. Owing to the rotatability of the lug on the screw, after sufficient frictional pressure of the lug against the base of the slot has been attained the screw will thereafter rotate without turning the lug while further pressing the lug downward. Thus the groove, including its side walls as well as its base, is preserved from scratching or other damage.

To enhance the frictional engagement of the edge of the guide 17 which contacts the edge 12 of the board, a lining 26 of rubber or the like may be applied to that edge of the guide.

After the T-square has been locked to the board 10 as above set forth, it is apparent that the draftsman may rest a triangle or any other appropriate drawing guide on the longitudinal edge of the arm 14 and draw the desired lines, as well as drawing lines along the longitudinal edges of the arm, with the use of both hands since he does not need to press the guide 15 against the board with one hand as is commonly required. By means of a simple loosening of the screw 22 to release the guide 17 from the arm .14, the T-square may readily be removed from the board to be applied and locked to another suitable surface.

However, since the edge of the guide 17, which faces and engages the edge 12 of the board 10 is perfectly flat, as is the edge 12, it is apparent that, without loosening the screw 22, the T-square may be lifted from the board in the manner illustrated in FIG. 4, owing to the flexibility of the usual arm 14 of a T-square, or similar device. This may be done by nudging the guide 17 upward with consequent slight but sufficient bending of the arm 14 to loosen the T-square from the board so that it may be lifted oif. Contrariwise, not shown in the drawing, the T-square may be removed from its locked position by nudging the guide 15 upward in the same manner. In re-positioning the T-square after it has been thus removed while the guide 17 remains locked thereto, the guide 15 may first be pushed down against the edge 11, as illustrated, or, preferably, the guide 17 may first be positioned against the edge 12 and then the guide 15 against the edge 11.

Also, both guides may be nudged upward or moved a downward simultaneously, with a slight arching of the arm, to thus remove or attach the device to the board.

From the foregoing it is obvious that any device used for a similar or equivalent purpose may be made while embodying the principles of the present invention, so long as the device includes an arm such as the arm 14 and a fixed guide such as the guide 15 on one end of the arm, and, further, so long as the device is applied to a board, table or the like having a surface at right angles to the edges of the board, table or the like. This is true regardless of the particular art in which the device may be used.

Although the invention has 'been described with particular reference to the embodiment illustrated in the drawing, such is not to be construed as a limitation upon the invention which is best defined in the accompanying claims.

The invention having thus been described, What is claimed and desired to be secured by Letters Patent is as follows:

1. A device of the kind described adapted to be applied to a support having a flat top surface and opposed edges at right angles to said top surface, comprising a flexible arm having parallel longitudinal edges and a top surface and a bottom surface, the arm being adapted to be laid on the top surface of the support with the bottom surface of the arm engaging the top surface of the support, a fixed guide secured to the arm and extending below the bottom surface of the arm thereby providing a shoulder adapted to engage one of said edges of the support, said shoulder lying in a plane at right angles to said arm, a movable guide slidably mounted on said arm and extending below said bottom surface of the arm to provide a shoulder adapted to engage the other of said edges of the support, the shoulder on the movable guide lying in a plane at right angles to said arm, said arm having a longitudinal groove in the top surface thereof, the movable guide having a transverse passage therethrough of a greater width than the width of the arm whence the arm registers loosely slidably in said passage, the movable guide having a threaded opening through a Wall thereof extending into said passage at right angles to said arm, a screw threadably registering in said opening and projecting through both ends of said wall, the end of the screw which projects into said passage having a disc-shaped lug rotatably mounted thereon, the lug having a diameter substantially equal to the width of said groove and registering in said groove and being adapted to be forced against the floor of the groove to lock the movable guide on said arm.

2. A device according to claim 1, said lug having at least the bottom portion thereof made of resilient material.

3. A device according to claim 1, said shoulder of the movable guide having a lining of resilient material thereon.

References Cited in the file of this patent UNITED STATES PATENTS 146,075 Jennings et a1 Dec. 30, 1873 291,248 West Jan. 1, 1884 379,361 Brown et al. Mar. 13, 1888 1,121,512 Krauss Dec. 15, 1914 1,399,935 Curts Dec. 13, 1921 2,002,676 Owens May 28, 1935 2,036,716 Nelson Apr. 7, 1936 2,118,747 Vest May 24, 1938 2,794,257 Blake June 4, 1957 2,995,823 Bowen Aug. 15, 1961 FOREIGN PATENTS 10,310 Great Britain 1889 

1. A DEVICE OF THE KIND DESCRIBED ADAPTED TO BE APPLIED TO A SUPPORT HAVING A FLAT TOP SURFACE AND OPPOSED EDGES AT RIGHT ANGLES TO SAID TOP SURFACE, COMPRISING A FLEXIBLE ARM HAVING PARALLEL LONGITUDINAL EDGES AND A TOP SURFACE AND A BOTTOM SURFACE, THE ARM BEING ADAPTED TO BE LAID ON THE TOP SURFACE OF THE SUPPORT WITH THE BOTTOM SURFACE OF THE ARM ENGAGING THE TOP SURFACE OF THE SUPPORT, A FIXED GUIDE SECURED TO THE ARM AND EXTENDING BELOW THE BOTTOM SURFACE OF THE ARM THEREBY PROVIDING A SHOULDER ADAPTED TO ENGAGE ONE OF SAID EDGES OF THE SUPPORT, SAID SHOULDER LYING IN A PLANE AT RIGHT ANGLES TO SAID ARM, A MOVABLE GUIDE SLIDABLY MOUNTED ON SAID ARM AND EXTENDING BELOW SAID BOTTOM SURFACE OF THE ARM TO PROVIDE A SHOULDER ADAPTED TO ENGAGE THE OTHER OF SAID EDGES OF THE SUPPORT, THE SHOULDER ON THE MOVABLE GUIDE LYING IN A PLANE AT RIGHT ANGLES TO SAID ARM, SAID ARM HAVING A LONGITUDINAL GROOVE IN THE TOP SURFACE THEREOF, THE MOVABLE GUIDE HAVING A TRANSVERSE PASSAGE THERETHROUGH OF A GREATER WIDTH THAN THE WIDTH OF THE ARM WHENCE THE ARM REGISTERS LOOSELY SLIDABLY IN SAID PASSAGE, THE MOVABLE GUIDE HAVING A THREADED OPENING THROUGH A WALL THEREOF EXTENDING INTO SAID PASSAGE AT RIGHT ANGLES TO SAID ARM, A SCREW THREADABLY REGISTERING IN SAID OPENING AND PROJECTING THROUGH BOTH ENDS OF SAID WALL, THE END OF THE SCREW WHICH PROJECTS INTO SAID PASSAGE HAVING A DISC-SHAPED LUG ROTATABLY MOUNTED THEREON, THE LUG HAVING A DIAMETER SUBSTANTIALLY EQUAL TO THE WIDTH OF SAID GROOVE AND REGISTERING IN SAID GROOVE AND BEING ADAPTED TO BE FORCED AGAINST THE FLOOR OF THE GROOVE TO LOCK THE MOVABLE GUIDE ON SAID ARM. 